1. Field of the Invention
The present invention relates to a vehicle front structure for a vehicle.
2. Description of Related Art
There has been known a vehicle front structure as described in Japanese Patent Application Publication No. 2004-9893 (JP 2004-9893 A), for example. In the vehicle front structure of this related art, guide means that causes a front wheel to deviate outwardly and move backward against a collision load is provided between a subframe and a suspension arm connected to a lower side of a front side member, so that the front wheel thus moving backward interferes with interference means provided in a vehicle-body member, thereby transmitting a collision energy to the vehicle-body member via the front wheel so as to disperse the collision energy.
In the vehicle front structure of JP 2004-9893 A, when a collision occurs in a vehicle front portion, the front wheel is moved backward while deviating outwardly, that is, the front wheel is moved backward while being distanced outwardly in a vehicle width direction. This configuration is quite effective because the configuration allows the front wheel thus moved backward along with the collision with a collision object to abut with the vehicle-body member (a rocker formed in the vehicle body), thereby consequently making it possible to largely reduce such a danger that the front wheel penetrates into a passenger compartment. Particularly, at the time of such a collision type in which a collision object collides with that part of a vehicle front portion which is distanced from a longitudinal central axis of the vehicle, that is, at the time of a short overlap collision in which the vehicle front portion collides with the collision object with a small overlap (overlap amount), the front wheel is surely distanced outwardly in the vehicle width direction and moved backward so that the front wheel thus moved backward abuts with the rocker, thereby consequently making it possible to largely reduce such a danger that the front wheel penetrates into the passenger compartment. In view of this, the above configuration is effective.
In the meantime, at the time when a collision occurs in the vehicle front portion, in order to immediately cause the front wheel to be distanced outwardly in the vehicle width direction and to move backward (in order to cause the front wheel to deviate outwardly and move backward), the following points are most important: that part of a connection portion between the subframe and the suspension member which is placed on a front side in a vehicle front-rear direction should be detached from the subframe at an early stage; and a deformation amount of the suspension arm with respect to an input along with the collision should be restrained. However, in a case where the connection portion between the subframe and the suspension arm is formed by use of a bush, it is necessary for the bush to be easily separated from the suspension arm so that the suspension arm is detached from the subframe at an early stage. In other words, it is necessary to lower strength and rigidity of the connection portion. On the other hand, it is also necessary to secure strength and rigidity necessary for the vehicle to run on a rough road, for example. However, it is difficult to satisfy both of these requirements incompatible with each other. Further, in order to restrain a deformation amount of the suspension arm with respect to an input along with a collision, it is necessary to reinforce the suspension arm itself by adding a reinforcing plate or by performing manufacture by iron forging. This results in an increase of unspring weight and an increase of manufacturing cost.